Questions tagged [beam]

Questions about the theory and applications of structural elements designed to resist bending.

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Why shouldn't we use Bernoulli beam theory if deformations and rotations are large?

I was going through the basic assumptions made by Bernoulli beam theory. I realized that one of the most important assumption in this theory is that the deformations and rotations of the beams are ...
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4answers
230 views

Is bending moment along a beam independent of the cross sectional area of the beam?

We know this that if the a cantilever beam (of any cross section) is fixed at one end and a transverse force is applied on the other, then it will bend. However, we just casually assume that the ...
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1answer
39 views

Why am I seeing a moment reaction at the supports for these beams in FEM?

Please observe the Finite Element model below, in ANSYS WorkBench, (Remote force behavior = Deformable). Also, please take a lot at the force and moment reactions at the fixed supports. I couldn't ...
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4answers
77 views

When we replace supports distributed reaction by point reaction in thin beams, is that considered an application of Saint-Venant principle?

I read about Saint-Venant principle which is about the effect of replacing forces by equivalent forces system that effect on the same small region of a rigid body, all examples I come across are on ...
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2answers
44 views

Help with understanding bending moment diagram of a frame structure

I have an exercise where I should calculate and draw a bending moment diagram for a frame structure. The frame structure is similar to the one below, image taken from http://structx.com: I would like ...
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2answers
53 views

Calculate shear and deflection for simply supported beam on different support height (like a staircase)?

I’m trying to calculate the beam deflection for an inclined beam. It’s only connected to floors (and not walls). The beam is a monorail and I want to test different shapes (tubes and I-beams). Plenty ...
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2answers
59 views

Shear and Bending Moment

A square tube is slid into a larger square tube. If a load is applied to the end of the inner tube, I would think that inner tube would mainly contact the outer tube in two locations as the load is ...
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1answer
24 views

Ways to stiffen a HSS profile?

I have an issue with a post that’s deflecting a little bit too much. Picture a 10 foot HSS c-channel section, used vertically as a post. Web/flange 4.5 x 1.75 @ 3/16 thick. Clients (friends) insisted ...
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1answer
53 views

Utilizing symmetry in statics problem

I am given the structure below, and supposed to find the forces occuring in $A, F, E, D, C$ and $B$. The task hints of using symmetry, as several forces are equal in magnitude. Supposedly, $A=B$, and ...
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1answer
74 views

Angular momentum of a multi-body system

I'm trying to compute the total angular momentum of a 3D multi-body, pendulum-like (as in, each body is connected to another one), mechanical system. Let us consider, for a simpler case, a 2D double ...
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2answers
50 views

strongest way to join ibeams at angle

I have a stock of surplus i-beams (aluminum) and am trying to build a structure where they are not always parallel. I understand i-beam is designed to be aligned vertically and optimized for strength ...
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24 views

Stresses due to combined loadings in a bent shaft supported at both ends

I was hoping someone might be able to help clarify where I might be going wrong with this question. I am being asked to essentially determine the maximum normal and shear stresses at the rigid support ...
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1answer
46 views

How to find the reaction at the pinned support A as shown in the picture? [closed]

Please help me solve the problem. I need to know the reactions at A for both the cases as shown. Please note that E is a roller, D is a pin support , B is an internal hinge and A for case 2 is a fixed ...
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3answers
89 views

Why is my FEM analysis producing unusually-large stress results?

This is my first time performing an FEM analysis, and I'm using the Ansys Workbench and Mechanical software. My situation is pretty straightforward--it's a straight beam that is fixed at one end and ...
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2answers
65 views

How to calculate the required prestressed jacking pressure to apply to a pre-tension concrete beam?

How does the fabricant of prestressed pre-tensioned beams calculate the equivalent pressure in the hydraulic jack (in bars) to the design prestress force (in kN)? Are there factors to multiply like a ...
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1answer
86 views

Is the calculated shear strain in a beam, engineering strain or tensorial strain?

Recently I came across a FEM code of a linear deformation beam element, and it made me wonder what is the correct relation between shear stress and shear strain in a beam element. In the beam element ...
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1answer
77 views

Finding Safety Factor for Plastic Snap Fit Cantilever

I'm trying to get a safety factor of $n\geq2$ for the root of my snap fit beam (pic at bottom of the post). I have gone through the calculations to get the SF at the root's edge from the geometric ...
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0answers
62 views

On rectangular section beam properties of plate stiffeners

I am trying to understand the expression of the vertical dynamic stiffness $K_T$ and the rotational dynamic stiffness $K_r$ which appears in this paper where they consider a semi-infinite plate ...
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3answers
465 views

What are the units used in beam bending equations? Do they matter?

I was just wondering whether or not the standard beam bending equations worked for all units. E.g. imperial and metric etc. From what I'm guessing it shouldn't really, since once we plug everything in ...
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2answers
94 views

Can a beam be too short to experience bending stress?

The question in the title says it all. I've got a a configuration where I'm using a bolt to support a load. The way its set up, the bolt will have a very short cantilever on it. When I calculate the ...
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1answer
68 views

Comparison of Shear Stress obtained from thin-walled beam theory and Timoshenko beam theory

I am studying the book "Structural Analysis with Applications to Aerospace Structures" by Craig. In Chapter 8 titled "Thin-Walled Beams", the authors derived the governing ...
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1answer
38 views

How to determine beam deflection with this unusual configuration (diagram attached)

So I've got a support system shown here in the attached image. Comparing configuration "A" to "B" it seems intuitive that "A" could support a larger load. The stubs are ...
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3answers
96 views

Is an axial force applied at the centre of a beam considered a compressive force, tensile force, or both?

I was looking through some course notes and realized that I never fully understood this concept. So, looking at the diagram below we can see that there is a 20kN axial force being applied in-between ...
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2answers
43 views

Where to place air, water and electric cables in a composite beam [closed]

If water, gas and electrical cables have to pass through three (3) openings provided in the cross section shown in Figure 2, with tangible and scientific arguments specify the adequate opening for ...
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2answers
182 views

Calculating the von mises stress in a 3D beam when given stresses and moments on both ends

I want to calculate the von mises stress in a given structural member. I want to generate a von-mises plot from this data. The forces are according to the local coordinate system of the beam. Also, I ...
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1answer
33 views

Calculating the load on the end of a beam

We ordered a really nice light for our dinner table and ordered a special "lightswing" seperatly. The light that we ordered however is heavier than the 'lightswing' is rated for. Please see ...
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40 views

How to use standard aluminium extrusions

How to use standard aluminum extrusions and accessories at Solidworks? I believe there are some libraries, but I don't know how to click or download them. Would you please teach me how to do it? Thank ...
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2answers
84 views

Find out the forces in members (as mentioned in the figure) of the truss by method of sections [closed]

I'm trying to find the forces in every member. But having a hard time resolving it. The Problem is to be solved by the Method of Sections of Truss.
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1answer
72 views

How to design an enclosure around the load cell (Beam type)?

Hardware and Electronics Used: Arduino UNO, HX711 ADC Load cell amplifier, Load Cell (2Kg); Currently, I am working on a project which requires me to put load cell along with the other circuitry in an ...
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3answers
147 views

Fun Force Problem - Basic Structure of Two beams supporting weight

I'm very new to engineering and thought I'd start with some basic problems and test them out with my own constructions! I've come up with this fun problem and would love some help solving it. Say you ...
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22 views

Adding tension to a model of a Timoshenko beam?

I am interested in modeling a Timoshenko beam: https://en.wikipedia.org/wiki/Timoshenko%E2%80%93Ehrenfest_beam_theory However, I would also like to add tension to the beam so that it can vibrate like ...
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1answer
68 views

How to calculate reaction moments and forces in a fixed axle with multiple point loads?

I need to calculate the maximum moment and reaction forces in an axle with both sides fixed in bearings, the axle is 1010mm long and has downwards forces of: 236kN at 403mm 86kN at 499mm 32kN at ...
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1answer
28 views

Diagrams of forces and moments of a statically determinate structure

I'm having difficulties with calculating the distribution of forces and moments in a statically determinate structure shown below. I'm especially confused about the arc part. Will there be only ...
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5answers
123 views

Exactly what makes steel-concrete composite beam better than pure steel?

A composite action beam may have a concrete section the top, carrying the compression load, and steel at the bottom, carrying tension. But I have always thought that concrete had lower strength for a ...
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3answers
81 views

How many support beams/rods needed for a firewood storage cabinet

I am building a firewood storage cabinet which should support around 100-150 kg of firewood. The cabinet is made out of wooden boards (...
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3answers
309 views

Why is it said that the flange of an I beam carries most of the moment?

It is often said for I beams that the flange carries most of the moment subjected to the beam, while the web carries most of the shear force. The latter is obvious from pictures like above, showing ...
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1answer
60 views

Cantilever beam

I want to design a cantilever addition. Over the driveway so I can't add supports. I want to use the calculator here https://calcresource.com/moment-of-inertia-rect.html But I'm having trouble ...
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1answer
29 views

If an airfoil underwent horizontal loading, would it stiffen the airfoil? [closed]

I am designing a wing for a Vertical Takeoff and Landing aircraft. I am trying to choose a wingtip winglet for my aircraft. One of the option is a aft-swept wingtip winglet. However, this structure ...
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1answer
60 views

Boundary conditions for a cantilevered Timoshenko Beam

I am trying to find out the boundary conditions for above given Timoshenko beam. The boundary conditions that I have derived are $x_1 = 0$ $$ \overline{u}_2^L = 0 $$ $$ \phi_3^L = 0 $$ $x_1 = \...
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4answers
116 views

Deflection of a fixed-fixed pvc pipe under self weight

I would like to start by saying I am not an engineer, so I apologize if this question seems simpleminded. I am making a manual tarp reel from pvc pipe, and I am trying to decided whether to use ...
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1answer
79 views

How to calculate the force of a cantilever beam at a given point of deflection?

I have put together a simple cantilever beam using finite difference modeling according to the following standard wave equation $$ρAy_{tt} = -EIy_{xxxx}$$ where $ρ$ is density, $A$ is cross sectional ...
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1answer
73 views

Simple cantilever beam deflection - what is the simplest way to add a damper?

I am looking at a simple cantilever beam deflection: I understand the general expression for deflection/force would be: $$y_s = \frac{Fx_s^3}{3EI}$$ $$F_p = \frac{3y_sEI}{x_s^3}$$ If you were going ...
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2answers
147 views

Multiple varying cross section beam with uniform loads

I have the following cantilever beam problem where I need to find the deflection of the tip at P. I tried to compute the deflection of the beam using Castignliano' s theorem as described in this ...
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3answers
88 views

Statically determinate system

The exercise is taken from linear algebra and its applications, prof. G. Strang Exercise 2.4.8 Truss I have already found that: m=n=8 → system is statically determinate, therefore solvable by ...
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13 views

double integration of continues beam to find the deflection at mid span [duplicate]

does any one know how to derive the deflection equation of a continues beam of three span of equal length and equal UDL load some of the steps of this explanation I didn't understand it Here's a link ...
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42 views

Continues beam deflection

does any one know how to derive the deflection equation of a continues beam of three span of equal length and equal UDL load Here's a link these two pictures shows my tries to solve the question
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1answer
39 views

Derivaiton of maximum deflection of a cantilever beam with intermediate load

I am trying to derive the maximum deflection of a cantilever beam. L is the length of the beam and a is the where force is applied. For the case 0<x<a, I use the method below and it gives me the ...
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3answers
147 views

How can deflection and spring constant of cantilever beam stack be calculated?

How can I calculate some properties of a stack of 2 bonded cantilever beams like in the image? Especially I am interested in the spring constant and deflection with force on random locations. However, ...
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0answers
29 views

Design of T-Beam

Please design a T-beam section size such that hf ≥ 125 mm, bw ≥ 200 mm, be ≥ 500 mm, d ≥ 300 mm, the concrete f'c strength is 25 MPa; the calculated concrete shear strength Vc that can be provided is ...
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1answer
134 views

How to check if bending moment diagram is correctly drawn

EDIT: I will state my test problem description and then my solution. But before that, I would like to apprise you of the absence of the actual description given during test (which happened in Zoom and ...

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